


One Little Mark

by TobytheWise



Category: Supernatural
Genre: Alternate Universe - Canon Divergence, Angel Castiel (Supernatural), Bottom Castiel (Supernatural), Bottom Dean Winchester, Cure for the Mark of Cain (Supernatural), Demon Dean Winchester, Happy Ending, Human Dean Winchester, M/M, Misunderstandings, Mpreg, Nesting, Pregnant Castiel (Supernatural), Soul Sex
Language: English
Status: Completed
Published: 2020-09-09
Updated: 2020-09-26
Packaged: 2021-03-06 22:14:30
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 6
Words: 6,287
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26376340
Author URL: https://archiveofourown.org/users/TobytheWise/pseuds/TobytheWise
Summary: When Castiel figures out a way to burn the Mark of Cain from Dean's body, he convinces Dean to let him in and say yes. The spell works, leaving Dean human and mark free. The only catch? When Castiel leaves Dean's body, a sliver of Dean's soul hitches a ride and creates a new life within Castiel. And to make matters worse, Dean has no memory of any of this.Castiel runs away, convinced this is better than Dean rejecting him. Confusion, confessions, and nest construction ensues all in time for a happily ever after.
Relationships: Castiel/Dean Winchester
Comments: 79
Kudos: 394
Collections: SPN ABO Bingo Round 5





	1. Bodyswap

**Author's Note:**

> This is written for the SPN A/B/O Bingo. Each chapter is a different square which you'll be able to see as the chapter title. I plan on updating every Wednesday and Saturday for the next six weeks. I hope you enjoy :D

Dean smiles as the angel walks into the room. He clenches his hands, rolling his neck back and forth. 

“Hello, Dean,” Cas breathes, carefully taking his trenchcoat off and staring down at Dean. Dean winks. 

“Heya, Angel.”

Cas doesn’t take the bait, instead looking down at his wrists and he undoes the cuffs of his dress shirt. Dean’s eyes widen as the tie and shirt come off one right after the other, leaving him bare from the waist up. 

“Cas,” he says slowly. “What are you doing?”

Instead of answering, Cas steps into the demon’s trap, walking right up to Dean’s chair. A strangled noise leaves Dean’s throat as the angel straddles his lap, his hands gripping Dean’s shoulders tight. 

“I have a bit of a proposition for you,” Cas says, getting comfortable in Dean’s lap. 

Dean tries to keep his racing heart under control. Since becoming a demon he hasn’t kept his feelings a secret. Why would he? Now he doesn’t have the capacity to care. He can live openly as a bisexual disaster, having any man or woman or demon or angel he wants. Well, all but one. 

“I’m listening,” he murmurs, licking his lips and letting his eyes flash black. 

Warm, supple lips begin peppering kisses against his jaw and Dean tilts his head back, his eyes closing as pleasure fills his chest. Dean’s cock is so hard where it’s trapped in his jeans, his breathing picking up speed. Cas’ teeth run over the side of his throat and he shivers. 

“I know you want me,” Cas tells him, his voice going impossibly lower, lighting a fire in Dean’s belly. 

“I ain’t hearing a question yet,” he grits out, his body breaking out into goosebumps as Cas’ mouth keeps working at his neck. He knows there’ll be a mark there. As a demon he could heal it away but he doesn’t want to, he wants to keep it as long as possible as a trophy of this moment. 

“I’m willing to let you have me.”

There’s a moment of silence as Dean’s ears begin to ring. “What?”

Cas pulls back, staring down into Dean’s eyes. “Do you still want me?”

Dean bites his bottom lip as Cas’ shimmies his hips, his ass riding against Dean’s hard cock. It forces the answer out. “Yes.”

“Then you can have me.”

“Just like that?”

Cas nods slowly. “With one condition.”

Dean sighs. “Right. Nothing in life can just be easy. Everything comes with a condition.”

The answer has Cas smirking slightly and a teeny tiny part of Dean’s chest warms. His hands clench against the arm of the chair he’s strapped in. He wants to reach out and touch Cas, take full advantage of this opportunity he’s apparently being given. 

“What’s the condition?”

“Say yes,” Cas breathes before touching Dean’s chin and tilting his head up, taking his lips in a gentle kiss. It’s soft. Too soft. Dean shoves his tongue forward between Cas’ lips, moaning when Cas reciprocates. “Say yes. Let me inside you, Dean.”

Dean moans at the absolute filthy words that are dripping with lust and want. He rides his hips up as much as he can while being restrained, trying to get some friction on his aching cock. He wants this. He wants Cas  _ so _ fucking badly. So he says the words Cas wants to hear. 

“ _ Yes _ .”

Cas hooks his thumb into the side of Dean’s mouth, holding it open as he kisses him again. Only this time the kiss fucking  _ burns _ . Dean’s eyes open wide, watching as bright blue light leaves Cas’ mouth and enters his own. 

There’s a moment of blind panic before Dean’s body slumps in his chair. 

“What the  _ fuck _ did you do?” Dean asks within his own mind. When he opens his eyes, he’s standing in a black room, Cas standing across from him. 

Cas just shrugs. “You said yes, Dean.”

“You fucker,” he says, stepping into Cas’ space, grabbing the front of his shirt. He’s breathing heavy, practically nose to nose. He’s so fucking angry. He feels like he’s losing control. To regain that control, Dean pulls Cas forward and kisses him. 

This kiss feels so much different then the first. Dean can feel the kiss through his entire body, like his very being is being intertwined with Castiel’s, which, he supposes is literally what’s happening. 

Cas’ mouth moves to this throat and Dean feels completely lost, unable to do anything but hold on for dear life. Pleasure has no peak like this. He can feel hands all over his body, warm mouths on his skin, a tug in his belly that leads him more and more to Cas. 

“Fuck,” Dean hisses out, heat fissuring deep in his belly, threatening to spill over. “Fuck, Cas. This feels--”

“I know. Your soul and my grace are literally touching, Dean. It’s incredible.”

“When you said I could finally have you, this isn’t what I expected,” Dean confesses between breathless kisses. 

“It’s so much better,” Cas says breathlessly. They find themselves on the floor and Dean has no idea where his clothes have gone but he can’t find it in himself to care. 

“Cas,” he moans out as he enters the angel, heat going through him as they connect. 

As they fuck, their mouths continue to move against each other. The longer they’re connected, the hotter Dean becomes. The Mark of Cain  _ throbs _ painfully, pulling at him, wanting to take over. There’s something else going on right now but he can’t focus on that, literally can’t think about anything but Cas, Cas,  _ Cas _ . Everything feels so good and his mind is going foggy with lust. 

“ _ Dean _ .” His name sounds closer to a prayer than anything else and with that thought, Dean closes his eyes and comes. 

Everything goes bright white. 

And then black. 


	2. Rejected Claim

Castiel crouches beside the bed, waiting impatiently for Dean to wake up. The spell he’d performed did exactly as it was supposed to. He went into Dean’s body and purged his soul of it’s darkness. The spell was so strong it was able to cure Dean of being a demon while also washing away the Mark of Cain. 

And if Castiel had to live with the consequences of that? Well, at least Dean was safe and sound. That’s all that really matters. 

“Are you sure it worked?” Sam murmurs, leaning against the wall, his eyes never leaving Dean. 

“I’m positive.” Castiel runs his finger over Dean’s arm, where the Mark of Cain used to be. 

Sam nods, chewing at the side of his thumb as they wait. 

The silence weighs heavily on them. The longer Dean sleeps on, the higher their worry becomes. What if something went wrong? What if Dean’s not  _ Dean _ anymore? 

Thankfully, before Castiel can spiral any further, Dean is stirring, his eyes blinking open slowly. He looks over, finding Sam and Castiel, the tiniest smile flashing across his face. 

“Hey fellas,” he murmurs, his voice breaking. “You look worried.”

“Dean?” Sam breathes, his voice breaking as he falls to his knees at Dean’s bedside, forcing his brother into a tight hug. 

Castiel stays where he is, letting them have their moment. Relief makes him breathless. His chest aches with how much he wishes to join Dean in that bed, to hold Dean and make sure he’s truly okay. But just as always, he pushes those wishes away. Now that Dean is human again, anything like that will be unwelcome. 

Castiel prepares himself to run the moment Dean’s eyes lock with his, not wanting to see the panic or disgust there. But instead, he’s greeted with welcoming, soft eyes. 

“Cas,” Dean murmurs, opening his arms, demanding a hug from Castiel as well. Castiel holds on just as tight, his stomach fluttering at the gesture, wondering if just maybe things will be different now. Maybe  _ they _ will be okay. 

Dean looks between the two of them, his eyes looking tired. “So,” he says, leaning back in his bed. “What the hell happened?” He looks down at his forearm, finding it empty. “I’m human. I don’t have the Mark of Cain,” he pauses, squinting at Sam and then Castiel. “Neither of you made any deals this time, did you?”

“No,” Sam says quickly. “Nothing like that.”

“Then what?”

Castiel looks away, trying to keep his emotions under control. Dean doesn’t remember. He doesn’t  _ remember _ . 

“Nothing you have to worry about,” Castiel says carefully, straightening and pushing his shoulders back. “You should just worry about getting your strength back, Dean.”

“Cas, come on.”

Castiel shakes his head. “It’s really not important. You’re okay, Dean. That’s what matters.”

Before he can hear anything else, Castiel turns and walks out of the room. He walks through the bunker. It shouldn’t surprise him that he ends up in the kitchen. It’s one of his happy places. A place he finds safe and great joy. 

Castiel goes through the familiar motions of taking out the tin of coffee grounds, measuring it out and dropping them into the coffee machine. He gets the maker going before putting the tin back. Then he pulls out two cups, setting them on the counter and waiting. He doesn’t even want coffee but it’s something to keep his hands busy, something attempting to take his mind off of the thing it’s currently swirling around. 

A rejected claim isn’t something Castiel ever thought he’d have to deal with. When an angel chooses their mate, it’s for life. Castiel didn’t even  _ mean _ to pick Dean as his mate, not really, not without his permission. He could go in there and explain everything knowing there’s the tiniest chance that Dean will choose him. But cutting this off now,  _ choosing _ to reject the claim himself feels safer. Maybe in the end his heart will heal. The same can’t be said if  _ Dean _ is the one to reject it. 

His hands shake as he fills up both cups. Now that they’re full he doesn’t really know what to do. Thankfully, that’s when Sam walks in. 

“He’s uh, he’s sleeping again,” Sam explains, picking up a cup of coffee with a nod of thanks before sitting down at the table. Castiel picks up his own cup, following Sam’s lead. 

Castiel’s hands tighten around his cup as he stares down at the black liquid. His stomach feels like there’s a cement bottom to it, weighing him down. The silence in the room grows tense until finally Sam clears his throat. 

“Dean said he’s worried about you.”

Castiel snorts. “He was just healed of being a demon but he’s worried about me?”

Sam shrugs, giving Castiel a look. “That’s Dean for you.”

“Yes,” Castiel murmurs, nodding his head gently. “Always worried about those he cares about before he worries about himself.”

Another moment passes. 

“Cas,” Sam whispers. “You gotta tell him, man.”

Castiel shakes his head, his heart skipping a beat. “I can’t.”

“He deserves to know. And it’s not like he doesn’t feel the same--”

Castiel cuts him off. “He would never want me, Sam.”

“He did--”

Castiel stands up, letting Sam finish. He dumps his coffee down the drain without drinking a single drop, his chest so tight it’s hard to breath. Lucky for him, angels don’t need to breathe. “He was a  _ demon _ . His inhibitions were lowered and he felt there were no consequences to his actions. I can’t,” Castiel pauses, running his fingers through his hair. “I  _ won’t _ hold that against him.”

“You’re not even giving him that choice.”

Castiel turns back to Sam, his shoulders slumping. Sam’s face shows off the hope he’s feeling and Castiel can’t find it in himself to mirror it. He wishes he had that kind of hope, but he just doesn’t, not right now. He shakes his head. “I’m  _ sorry, _ ” he breathes before his wings are flapping and he’s flying away. 

Castiel lands soundly in a field outside of Wisconsin. He looks up at the sky, wishing there was someone there he could pray to, someone he could trust with the information he’s holding. His hand goes to his middle, feeling the life he and Dean somehow created together. There’s an ache in his chest that’s widening every so slowly, cracking him open. Oh how desperately he wishes Dean could be the one to fill it. 

Dean with his gentle eyes and calloused hands. The hunter who’s always fierce while also being so achingly tender around those weaker than him. The same man who raised his brother and takes care of every child that crosses his path. Castiel knows without a doubt that if he brought this up to Dean, he’d jump on the opportunity for them to finally be together. But he doesn’t want it like this. He doesn’t wish to take Dean’s choice away. He wants Dean to pick  _ him _ just because he loves Castiel and the thought of being without him is too much. Call him selfish but the closer Castiel gets to humanity, the more he  _ wants _ and  _ needs _ . 

Castiel feels his strength leave him the further away from Dean he gets. His grace is crying out, literally weeping within himself as it longs for the other half of the claim. But Castiel’s always been good at denying himself and this is no different. 

Eventually Castiel will have to fly back to the Winchesters and face Dean. But for now he takes this moment to look at the stars and think about the life inside of him, hoping that’ll be enough to get him through all of this. 


	3. Mpreg

Dean turns the page, his eyes going blurry as he stares at the words. He rubs at his eyes before trying to focus on the words once more. After a few times he groans, shutting the book with a slam and slumping in his chair. 

Dean picks up his phone, checking for messages and sighing when there’s nothing. Ever since he was brought back to the land of the living, or whatever the equivalent is for purging his soul of all things demonic is, Cas has been awol. 

It’s not like the angel has to be at the bunker twenty four seven but usually he at least stops to check in. But Dean hasn’t seen him since the day he woke up with green eyes instead of black. 

There’s a little nudge at the back of Dean’s mind that whispers that he’s missing something, something really, really fucking important. But if there was, Cas or Sam would have said something, right?

Dean stands up with a long sigh, raising his hands over his head and listening as his back cracks and pops. He walks to the kitchen, pouring himself another mug of coffee. There’s an ache in his chest as he goes, a phantom presence missing. Dean normally pours two mugs full, one for himself and one for Cas. But Cas isn’t here these days. 

He needs to get his head on straight and focus. 

Sipping his coffee, Dean makes his way back to the library. He runs his fingers over the cover of the book. This would be so much easier if they had their  _ angel _ here. Someone who could zip across the country in the blink of an eye instead of having Dean search the books for an alternative way at stopping this monster. 

“Fuck it,” Dean murmurs to himself, picking up his phone and dialing Cas’ number. It rings. And it rings. And it rings before going to voicemail. “Son of a bitch.”

Dean stands up again, his heart sinking. There’s a pull deep in his gut, a  _ longing _ to have Cas here, in his space, in their  _ home _ . He misses his best friend. So Dean does the only thing he can think to do. 

“Heya, Cas,” he says, closing his eyes and tilting his head up. “I hope you’ve got your ears on, buddy. It’s been awhile since we’ve seen you. Since, ya know, I’ve seen ya.” Dean runs his hand through his hair, trying to find the right words. But instead he gets straight to the point. “Sammy’s been having problems on the hunt he’s working. I could really use your help, man.” Then he softly adds, “please?”

Dean opens his eyes, looking around. His stomach somehow sinks even further. Just before he’s prepared to give up all hope, the sound of fluttering wings hits his ears. Dean can’t help but smile at the familiar sound. 

“Hey,” he breathes as Cas pops into existence. But instead of the usual perfect landing, Cas stumbles over his feet and falls against the table, his hands gripping the table tight in order to keep himself upright. “Cas!”

Cas looks up, his eyes wide and wild, his hair a mess. Dean looks over his face, finding it strangely pale. 

“I’m fine,” Cas says right away, his voice making Dean shiver. God, he’s missed that voice. 

“You don’t look fine. What’s going on?”

“I said I’m fine, Dean.” Cas looks around, his eyes landing on the books Dean’s been reading through. “What’ve you got?”

Dean stares a long moment as Cas moves over to the chair across from Dean’s, flopping down. Dean’s brow raises in confusion at the display, so used to Cas’ grace. “Uh,” he clears his throat. “Yeah, right. Sam’s working on a case in Florida. We need you to fly over to Germany where they have a golden stake crafted by a group of mute monks.”

Dean slides the address of the monastery over. Cas looks down at it before looking away, his face blank. “I’m sorry but I can’t.”

“You? You can’t?”

Cas stands up and moves to the bookshelves. “Now that I’m here, I will help you find an alternative.”

“Cas, buddy, what’s going on with you?”

“It’s nothing to be concerned about.”

“If it’s nothing to be worried about then get your feathery ass over to Germany and back.”

Cas’ eyes narrow and Dean swallows, trying to keep his reactions under control. “I can’t,” he grits out. 

“Then you need to tell me what’s going on. If there’s something we can do--”

“There’s not. Drop it, Dean.”

Dean rubs at his face tiredly, opening this stupid book back open. He gets lost in the text. He’s not sure how long they go like that, reading silently before Dean’s eyes land on the answer. “Hell yeah,” he says with a wide smile, texting Sammy the answer before slamming his book closed once more. 

He tosses the book to Cas. “Can you put that away? Top shelf right there,” he says with a nod towards the bookshelf. 

Cas rolls his eyes but does as he’s asked, reaching up on his tiptoes and putting the book away. 

That’s when Dean sees something that steals his breath. Cas’ trench coat has fallen open, his shirt tight across his stomach. Said stomach is… well, it’s round. The only time Dean has seen a belly like that is when someone is pregnant. 

“Cas?”

Cas finishes putting the book away before turning to Dean. When he realizes Dean is staring at his stomach he pulls his trenchcoat around himself, his hands covering his stomach. 

“Cas, what the hell?”

“I can explain.”

“Well, I should hope so! Are you  _ pregnant _ ?” 

Dean’s ears ring and his heart races. His stomach is sinking down to his toes and he feels like he might be sick. He’s in love with someone who’s gone out and somehow managed to get pregnant with someone else, someone who is  _ not _ Dean. Fuck. Why does it hurt so bad? It’s not like Cas would ever pick him, anyway. 

“Yes,” Cas says simply, his face looking stricken. Dean opens his mouth to ask a question but Cas cuts him off. “Please,” he whispers. “Please don’t ask me a question you can’t handle the answer to.”

Dean freezes, his heart picking up speed. This moment, whatever the fuck is happening grows so tight the slightest breeze would snap it. He takes a deep breath and asks. “Who?”

“Who’s the other father?”

“Yeah, Cas, who’s your baby daddy?”

Cas looks away, his hands coming to rest against his bump. “I’m afraid to tell you,” he confesses. “I’m afraid you’re going to hate me.”

“Cas,” Dean murmurs, taking a step forward. When Cas doesn’t react he moves the rest of the way, closing the distance between them. He puts a hand on Cas’ forearm, ignoring the way they both shiver with the touch. Something inside of him is drawing him to Cas to the point that Dean wants to hug him, hold him,  _ kiss him _ . Something deeper than just his feelings, something tugging at his very soul. “Cas, I could never hate you.  _ Never _ .”

Cas’ blue eyes water. “I hope you’re right,” he whispers before dropping the biggest bomb of Dean’s life. “Dean. The baby is yours.”


	4. Matching Claim Marks

Dean opens his mouth to say something but nothing comes out. What? How?  _ What _ ?

“I can explain,” Cas says quickly, one of his hands reaching out and gripping Dean’s wrist. “Just please, hear me out?”

“Of course,” he gets out, his voice breaking. He looks into Cas’ blue eyes, eyes he’s come to trust and listens to him explain. In order to purify his soul and rid him of the Mark of Cain, Castiel poured his grace into Dean. They had-- Dean takes in a shaky breath, cursing himself for not remembering  _ this _ . They had what equates to some sorta soul sex. And when Cas flew back into his own body, a little sliver of Dean’s soul hitched a ride and that somehow made a baby. 

“Well fuck,” Dean whispers, not knowing what else to say. 

“I was afraid. I’m sorry, Dean.”

Dean pulls back, ignoring the little whimpering noise that leaves Cas. He needs a small amount of distance to think. “Were you afraid I wouldn’t want this? Is that it?”

Cas shakes his head. “The opposite. I was afraid you’d commit yourself to me because of the baby. I was afraid you’d tie yourself to someone you didn’t actually love because you felt  _ obligated _ . You are known for your self sacrificing, Dean. This wasn’t a sacrifice I wanted you to make.”

“Damn it, Cas,” Dean grits out before he’s storming towards the angel. Cas’ eyes widen a moment before they’re shutting as Dean cups Cas’ face between his palms and kisses the angel. 

Why the fuck did they wait so long to do this? 

The kiss is everything Dean’s ever hoped it would be. Cas’ lips are subble against his own and a little chapped. Cas kisses back just as fiercely. Dean’s lips move, opening slightly and he’s rewarded with Cas’ tongue sliding into his mouth. 

When he pulls back, their noses brush and Dean is struck with how fucking  _ intimate _ and  _ domestic _ the gesture is. He honestly never thought he’d get this, tried not to let himself dream it. 

“Cas,” he whispers. “If you think being tied to you is some form of self sacrificing then you have no idea of the feelings I have for you.”

“Then tell me,” Cas says, his voice borderline broken. “Please.”

“I love you,” Dean says all in one breath, needing to get it out. 

And then they’re kissing again. Cas’ hands go around Dean’s back, plastering their fronts together. That bump presses against Dean’s stomach and something inside of him clicks into place, almost like something he didn’t even realize was missing has come home. 

They stumble along towards Dean’s room, slowly losing their clothes as they go, just needing to get hands on skin as fast as possible. Dean feels giddy. He feels free. He’s held onto this secret so fucking tight, always pushing his own desires away thinking that there’s no way Castiel could ever feel the same. 

“I love you, Dean,” Cas says, his lips against Dean’s jaw. “Love you so much. I’d fight Heaven and Hell by your side if you asked me.”

“You already have,” Dean tells him, wondering if he should be embarrassed by the awe in his voice. But he’s not, can’t be, not when Cas is looking at him with such soft eyes. 

When they make it to Dean’s room, they finish getting undressed. Dean’s eyes find Cas’ belly. It’s extended and round. It’s  _ beautiful _ . Dean’s eyes snap back up to Cas’ eyes, a fire burning in his own belly, one he knows will only be quenched by Cas. 

Dean is as gentle as he can be as he lays Cas down onto his bed, pressing open mouthed kisses all over Cas’ exposed skin, smiling as he does. When he looks up, Cas is smiling right back. Dean’s stomach swoops at the sight. 

“I wanna ride you,” he breathes against Cas’ skin. “Can I?”

Cas’ hand jumps to Dean’s hip, pulling Dean into his lap. His fingers squeeze almost painfully and Dean moans as he feels his ass suddenly slick and loosen. “Jesus,” he hisses out. “Fuck, warn a guy, Cas.”

“My apologies,” Cas says though his eyes say anything but. He helps Dean raise up before letting Dean slowly sink down onto his cock. 

Dean looks up at the ceiling, breathing through his nose as he works through the overwhelming feeling of having Cas inside him. Cas’ hands slide up Dean’s stomach and chest, then over his thighs, like he can’t stop touching Dean now that he has permission. 

Dean leans down, kissing Cas as he rides the angel’s dick. Their breaths mingle between their lips as they make love, because that’s what this is, they’re coming together to make love. The feel of Cas’ belly bumping against Dean’s is the reminder that they made a new life together.

“Fuck,” Dean gasps out as Cas wraps his hand around his erection, stroking him hard and fast.

Cas’ other hand grips Dean’s shoulder, the same shoulder his mark used to be. Dean’s right hand goes to the middle of Cas’ chest. He’s not sure what’s happening, only that he embraces it, leans into it as his body lights up with pleasure. There’s heat under his palm and heat at his shoulder. It’s suddenly blindingly too much before snapping.

It’s only a matter of moments before Dean is crying out and coming. His ass tightens around Cas’ cock, pulling the orgasm right out of him. Cas comes with his eyes clenched shut and his fingers dig into Dean’s thighs. 

When Dean can finally breathe again, he opens his eyes, staring in wonder at the perfect handprint in the center of Cas’ chest. His fingers go to his shoulder, finding the skin raised and red once more. Without being told, Dean knows he’s been claimed and he’s claimed Cas right back. They belong to each other in a way that goes beyond the natural. He doesn’t care if it’s an angel thing or just a  _ Cas _ thing, it feels right. 

Afterwards, they lie on their sides facing each other, Dean’s hand resting on Cas’ belly. “I love you,” he says again, the words barely above a whisper. 

“I love you,” Cas says back, his eyes crinkling at the corners with his smile. Dean leans over and kisses his nose, snorting when Cas’ wrinkles it. 

“I love you, too,” Dean whispers to Cas’ belly. And he knows it’s the truth. He might have just realized they exist less than an hour ago, but already his chest is expanding, making room for their baby. 


	5. Applewood/Old Books/Earl Grey

Castiel searches through the bunker kitchen frantically, something deep inside of him screaming for him to find the final piece of the puzzle. His left hand goes to the side of his overgrown belly, rubbing the area his little one keeps kicking. He pushes gently, rewarded with another kick against his hand. 

“Don’t worry,” he whispers to himself. “I’m sure we’ll find just the thing.”

He opens a cabinet, finding Sam’s supply of tea. His eyes narrow as he looks through the boxes. He picks up the Earl Grey, lifting it to his nose and breathing it in. Castiel’s eyes close as the smell hits his nose, washing over him. 

Oh, this is it. This is perfect. 

“Are you having a religious experience with that tea, buddy?” Dean asks with a little smile, stepping into Castiel’s space. His hands go around his middle, holding his belly. Dean kisses just behind his ear and a soft sigh leaves Castiel’s lips. He’s not sure he’ll ever get used to the way Dean shows him small affections like this. 

“I might be,” Castiel says back, smiling as Dean nuzzles against the side of his head. “Are you jealous?”

“Should I be?”

“Probably,” Castiel confesses. “This is the perfect smell to finish my nest.”

“Your nest? Is that like an angel thing?”

Castiel feels his cheeks heat up. He’s been keeping his nest a secret for the last few weeks, using his grace to keep the Winchester’s away from it. He wanted it to be perfect before he showed his mate. And now with these packets of tea, a rightness fills his chest.

“Yes,” he says, turning around and facing Dean. “It’s a place that makes me feel safe and a place to have our baby.” 

Dean nods his head, his brows furrowed. “Okay. Can I see this nest, since I’m your mate?” Castiel’s heart stutters with that word, still in awe that Dean, the Righteous Man, the one who stole Castiel’s heart and made him see the beauty of humanity, is his  _ mate.  _ “Or is this something just for you?” 

“You can see it. Come on,” Castiel says, taking Dean’s hand and leading him into the library. Now that he  _ wants _ Dean in his space, the traces of grace he’s left welcome Dean in instead of repelling him. 

Castiel leads him towards a back alcove where he’s placed a blanket over the entrance. They both duck inside and Castiel breathes easily, his chest loosening. He sits down in his nest, tugging Dean down with him. 

“This is…” Dean’s voice trails off as his eyes take everything in. There’s a tiny smile on his face as his fingers trace all the soft blankets within the nest. “Would you be offended if I said this was adorable?”

Castiel ducks his head, smiling. There’s something deep within Castiel that flutters with joy, the little life inside of him jumping in response. “Thank you, Dean,” he says in response. He lays himself down and without being asked, Dean lays beside him, spooning up behind. Castiel feels warm all over. He’s safe, he’s happy, things are  _ good _ . There’s no current big bad and the only thing they have to worry about is making sure everything is ready for their baby. 

“This is perfect,” Dean says, kissing Castiel’s ear. “I love you, Cas.”

Castiel can’t stop the smile on his lips. “I love you too.”

He takes a deep breath. Applewood drifts into his nose from the old flannels he’d found in Dean’s closet. The old book smell comes in from being surrounded by old library books. He takes the tea bags out of the box, setting them beside his nest, letting the Earl Grey tea smell sink in with the rest. It’s perfect. 

“Oh,” Dean breathes as his hand touches the side of Castiel’s stomach, feeling their baby kick. “Sometimes I still can’t believe this is happening. I feel like I should be freaking out.”

“There’s still time,” Castiel says with a snort. 

“Nah.” Dean’s nose runs over his skin, his hand rubbing where their baby keeps moving. “I ain’t gonna freak. The only thing I’m nervous about is worrying about you and wondering if I’ll be a shit dad.”

Castiel flips around so they’re face to face, his hand cupping Dean’s cheek. “You’re already an amazing father, Dean. I have no doubt our child will be loved beyond measure.”

“Yeah,” Dean whispers with a small smile. “They’ve got two headstrong dads and a moose for an uncle.”

Castiel snorts before leaning up on his elbow and kissing Dean, just because he can. His stomach flutters and his heart races in the most pleasant way. “My nest is  _ almost _ perfect,” he whispers against Dean’s lips. 

“ _ Please _ tell me it’s a sex thing?”

Castiel chuckles warmly. “It’s a sex thing,” he says back, moaning when Dean’s mouth moves from his mouth to his neck. Every single touch is electric, his body coming alive under Dean’s hands. 

Dean opens both of their slacks until their cocks are exposed. Castiel snaps his fingers, thankful that his grace hasn’t decided this was a good moment to backfire. Dean smiles as he picks up the lube Castiel has just ‘mojoed’ from Dean’s room, using it to slick both of their cocks before taking them both in his hand. 

“Oh,” Castiel breathes, overwhelmed with pleasure. Between Dean’s grip and feeling his dick pressed up against Castiel’s, he knows this won’t take long. “Yes, just like that. Dean.”

“I’ve got you, Angel,” Dean whispers back, kissing Castiel once more. They pant into each other’s mouths as Dean works them over. “Fuck, Cas.”

The sound of Dean’s voice breaking with pleasure is enough to send Castiel over the edge, coming hotly over Dean’s fist. Dean isn’t far behind, chasing his own pleasure. When he comes, he bites at Castiel’s neck, no doubt leaving a mark that only makes Castiel sink back into his nest with content pleasure, knowing he’s marked by his mate. 

With this christening, Castiel feels bone deep contentment. This is the place he’ll welcome his baby into the world, the place he feels most safe and sound. When Castiel looks over, he finds Dean’s face soft with sleep and his heart clenches. It’s only a matter of days before their baby will be welcomed into the world and Castiel knows without a shadow of a doubt that he’s ready. 


	6. Pups

**Notes for the Chapter:**

> Thank you to everyone who stuck around to read and leave me kudos and comments, y'all are amazing. This is the final chapter of the fic.   
> I wanted to give a quick shoutout to my amazing beta, Shikaro <3 <3 
> 
> I hope you all enjoy the final chapter!

Dean takes the cool towel, using it to wipe Cas’ brow. They’re laying in Cas’ nest, Cas on his side as he breathes through the pain. 

“It’s almost time,” he says, his blue eyes staring at Dean. Dean’s chest clenches with equal parts excitement and worry. He wants Cas to be okay. No, he  _ needs _ Cas to be okay. They’ve been through so much and now that they’re finally together the way Dean’s always dreamed, he can’t even handle the thought of losing that. 

“You’re doing great,” Dean says, not knowing what else to say. He leans down and kisses Cas’ sweaty brow. 

“Close your eyes,” Cas tells him before taking his hand, giving it a reassuring squeeze. “You’re about to meet our baby, Dean.” Dean closes his eyes, putting all of his love and trust into his mate, and yeah, he’s finally getting used to the idea of Castiel, angel of the Lord, being his  _ mate _ . 

Bright blue light fills the nest, growing brighter and brighter. It almost hurts Dean’s eyes despite the fact that they’re clenched shut. The feel of Cas’ belly beneath his palm slowly grows hotter and hotter the brighter the light becomes. 

“Cas?” 

“It’s okay. It’s part of it. They’re almost here.”

Cas makes a pained noise that has Dean tensing. But then, all at once, it’s over. The light is gone, the heat under Dean’s palm is cooled and  _ squirming _ ? He slowly opens his eyes.

“What the?”

His eyes flit up to Cas’ face, finding the angel staring down at their baby, tears glistening his eyes. Dean’s not sure Cas has ever been more beautiful. He finally looks down as well, his chest aching with the amount of love overwhelming him. 

“We have a son,” he whispers, his voice thick with emotion. His finger runs over their baby’s face, watching as he leans into the touch. He opens his eyes for only a moment, long enough for Dean to see his bright golden eyes. “Woah.”

“He’s a nephilim,” Cas explains. “Half human and half angel. He’ll grow far faster than a human child and have powers and wings like me.”

Dean swallows. “He’s perfect, Cas.” He looks into Cas’ eyes and smiles before leaning over and kissing his lips. “I love you. Thank you for fighting for me over and over and over again.”

“I’ll always come when you call,” Cas says with a little smirk. 

“How’re you feeling?”

“Good as new,” he tells Dean, lifting his shirt and showing off his toned stomach. 

“Damn,” Dean murmurs. “Perks of an angel, huh?”

They fall into silence, both staring down at their son. He’s so quiet and soft, so different than the average newborn scene you see in movies. “Did you pick out a name?” Dean asks, running his fingers through the baby’s dark hair. 

“I was thinking Jack. Jack Winchester.”

Dean can’t contain his smile. “I like the sound of that.”

It’s not long after that they leave Cas’ nest, bringing Jack out to meet Sammy. As he watches his brother hold his son for the first time, Dean is struck all over again with how fucking lucky he is. He has his mate, his son, his brother. His soul is his own once more and he’s no longer a slave to the Mark of Cain. 

Dean’s hand goes to his shoulder, feeling the way his skin is raised from Castiel’s mark. His eyes find Cas’ where he sits next to Sam. They share a look, one filled with wonder and affection. Dean refuses to take this second chance for granted. He’s gonna do his damndest to take care of Jack, to always remind Cas how he feels, to keep his brother safe. 

His life used to look so bleak. Dean assumed life would only be worth ending in a blaze of glory. Now he has so much to live for. 

What a difference one little mark makes. 


End file.
